Oscilloscope Lessons — Worksheets — Architecture of Grace

The Oscilloscope · Lesson 1 of 17

Power and a trace

Turn it on. Pick a signal. Make a line big enough to see.

Name and date

Key words

oscilloscopetracesignal

Main idea

An oscilloscope draws a signal as a line, so you can see it.

In my own words

Try it · on the scope

1

Step 1

Turn the scope on.

2

Step 2

Pick the sine source.

3

Step 3

Turn up the height until the wave is at least one box tall.

4

Step 4

Look at the line. Find the top and the bottom.

Short answer 1 · How many boxes tall is your wave, top to bottom?

Record the numberboxes

Short answer 2 · What is the height setting you used?

Record the numberV

Sketch · Draw the trace you see.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · Why is seeing a signal useful when you cannot hear or touch it?

Reflection

What changed on the screen when you turned the power on?

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The Oscilloscope · Lesson 2 of 17

The grid: divisions

The screen is a grid. Count the boxes. Every reading starts with a count.

Name and date

Key words

divisiongraticulegrid

Main idea

The screen grid is a ruler. Ten boxes across, eight boxes tall.

In my own words

Try it · on the scope

1

Step 1

Set 1 volt per division.

2

Step 2

Set 1 ms per division.

3

Step 3

Count the boxes across the screen.

4

Step 4

Count the boxes up and down.

Short answer 1 · How many boxes across?

Record the numberboxes

Short answer 2 · How many boxes up and down?

Record the numberboxes

Sketch · Draw the grid lines and one wave on top.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · Name one other tool that uses a grid to measure.

Reflection

Why does a scope screen have a grid at all?

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The Oscilloscope · Lesson 3 of 17

Volts per division

Height is volts. Boxes tall times volts per box.

Name and date

Key words

volts per divisionamplitudepeak to peak

Main idea

Height on the screen is volts. Boxes tall times volts per box gives the height.

In my own words

Try it · on the scope

1

Step 1

Sine source. Set the height to 2 V.

2

Step 2

Choose volts per division so the wave is 3 to 5 boxes tall.

3

Step 3

Count the boxes from the top of the wave to the bottom.

4

Step 4

Multiply: boxes × volts per box.

Short answer 1 · Boxes tall, top to bottom?

Record the numberboxes

Short answer 2 · Height you read: boxes × volts per box

Record the numberV

Sketch · Draw the wave and mark its top and bottom.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · If you halve the volts per division, what happens to the wave on screen?

Reflection

Did your reading match the height setting? If not, what happened?

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The Oscilloscope · Lesson 4 of 17

Time per division

Width is time. One cycle across is the period.

Name and date

Key words

time per divisionperiodtimebase

Main idea

Width on the screen is time. One cycle across is the period.

In my own words

Try it · on the scope

1

Step 1

Set the frequency between 200 and 300 Hz.

2

Step 2

Choose ms per division so about two cycles show.

3

Step 3

Count the boxes for one full cycle, crest to crest.

4

Step 4

Multiply: boxes × ms per box. That is the period, T.

Short answer 1 · Boxes for one cycle, crest to crest?

Record the numberboxes

Short answer 2 · Period T you read: boxes × ms per box

Record the numberms

Sketch · Draw two cycles and mark one period.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · Two waves: one takes 2 ms per cycle, one takes 8 ms. Which is faster?

Reflection

What happens to the picture when you make ms per division bigger?

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The Oscilloscope · Lesson 5 of 17

Frequency from the period

Frequency is one divided by the period. Read T, then compute f.

Name and date

Key words

frequencyhertzperiod

Main idea

Frequency is cycles per second. It is one divided by the period.

In my own words

Try it · on the scope

1

Step 1

Set any frequency from 100 to 1000 Hz. Do not look at the number yet.

2

Step 2

Show one to four cycles.

3

Step 3

Read the period T in ms.

4

Step 4

Compute f = 1000 ÷ T. Then compare with the real setting.

Short answer 1 · Period T you read

Record the numberms

Short answer 2 · Frequency you computed: 1000 ÷ T

Record the numberHz

Sketch · Draw the cycles you used to read T.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · A period of 4 ms: what is the frequency? Show your steps.

Reflection

How close was your answer to the real frequency? What would make it closer?

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The Oscilloscope · Lesson 6 of 17

Sine, square, triangle, saw

Same pitch, different shape. Look at all four.

Name and date

Key words

sinesquaretrianglesawtoothtimbre

Main idea

Same pitch, different shape, different colour of sound.

In my own words

Try it · on the scope

1

Step 1

Keep the same frequency and height.

2

Step 2

Look at the square. Then the triangle. Then the saw.

3

Step 3

Go back to the sine.

4

Step 4

Press Hear it on two shapes if the room allows sound.

Short answer 1 · Which shape has flat tops? Write its name.

Record the number

Short answer 2 · How many shapes did you look at?

Record the numbershapes

Sketch · Draw two different shapes, one above the other.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · Which shape would you pick for a soft sound? Why?

Reflection

Same note, different shape. What is different about the sound?

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The Oscilloscope · Lesson 7 of 17

The trigger

Without a trigger the trace runs. A trigger holds it still.

Name and date

Key words

triggerrising edgefalling edge

Main idea

A trigger tells the scope where to start drawing, so the picture holds still.

In my own words

Try it · on the scope

1

Step 1

Turn the trigger off. Watch the trace run.

2

Step 2

Trigger on the rising edge. The trace holds still.

3

Step 3

Trigger on the falling edge. Look at the left edge of the screen.

4

Step 4

Find the small gold mark at the left edge.

Short answer 1 · With the rising edge, is the wave going up or down at the left edge?

Record the number

Short answer 2 · How many cycles are on the screen?

Record the numbercycles

Sketch · Draw the trace with the trigger on the rising edge.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · Where on the wave does a rising-edge trigger start the picture?

Reflection

Why would a running trace be hard to measure?

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The Oscilloscope · Lesson 8 of 17

Two channels

A second trace on the same screen. Make both fit.

Name and date

Key words

channelcomparevolts per division

Main idea

Two channels put two signals on one screen so you can compare them.

In my own words

Try it · on the scope

1

Step 1

Turn channel 2 on.

2

Step 2

Set channel 2 to half height (50%).

3

Step 3

Choose volts per division so both traces fit: 2 to 7 boxes.

4

Step 4

Compare the two heights.

Short answer 1 · Boxes tall for channel 1?

Record the numberboxes

Short answer 2 · Boxes tall for channel 2?

Record the numberboxes

Sketch · Draw both traces. Use two different lines.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · Name a pair of signals a scientist might want to compare.

Reflection

When would you want two signals on one screen?

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The Oscilloscope · Lesson 9 of 17

Phase

Two waves can be alike but shifted in time. That shift is phase.

Name and date

Key words

phasedegreesshift

Main idea

Phase is how far one wave is shifted from another, measured in degrees.

In my own words

Try it · on the scope

1

Step 1

Channel 2 on, same height as channel 1.

2

Step 2

Shift channel 2 by 90°. Look at where its crest lands.

3

Step 3

Shift by 180°. It is upside down.

4

Step 4

Try 360°. What do you see?

Short answer 1 · At 90°, how many boxes apart are the two crests?

Record the numberboxes

Short answer 2 · At 180°, when channel 1 is at its top, where is channel 2?

Record the number

Sketch · Draw both traces shifted by 90°.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · Two waves 180° apart: what happens if you add them?

Reflection

What does 180° out of phase look like, in your own words?

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The Oscilloscope · Lesson 10 of 17

Amplitude and loudness

Double the height and hear it. Twice the volts is about 6 dB more.

Name and date

Key words

amplitudeloudnessdecibel

Main idea

Taller wave, louder sound. Twice the volts is about 6 dB more.

In my own words

Try it · on the scope

1

Step 1

Set the height to 1 V. Press Hear it.

2

Step 2

Set the height to 2 V. Press Hear it.

3

Step 3

Write what changed and what stayed the same.

4

Step 4

Twice the volts is about 6 dB more. Record it.

Short answer 1 · Height one

Record the numberV

Short answer 2 · Height two, and the change in dB

Record the numberdB

Sketch · Draw the 1 V wave and the 2 V wave on the same grid.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · Why is the decibel a useful unit for loudness?

Reflection

Did the pitch change when you doubled the height? Why or why not?

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The Oscilloscope · Lesson 11 of 17

Harmonics: a square is many sines

Build a square wave out of sines, one at a time.

Name and date

Key words

harmonicfundamentalFourier

Main idea

A square wave is a sine plus smaller, faster sines. Those extras are harmonics.

In my own words

Try it · on the scope

1

Step 1

Pick the square source.

2

Step 2

Set Build from sines to 1. That is just a sine.

3

Step 3

Set it to 3. Then 5. Then 9 or more.

4

Step 4

Watch the corners get sharper.

Short answer 1 · How many sines did it take to look almost square?

Record the numbersines

Short answer 2 · Are the harmonics odd numbers, even numbers, or both?

Record the number

Sketch · Draw the shape at 3 harmonics.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · Why do the corners get sharper as you add more harmonics?

Reflection

Why can a flute and a clarinet play the same note and still sound different?

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The Oscilloscope · Lesson 12 of 17

Measure a pulse

A heartbeat-style pulse repeats slowly. Slow the timebase and count beats.

Name and date

Key words

pulsebeats per minuteperiod

Main idea

A pulse repeats slowly. Count the time between beats to find the rate.

In my own words

Try it · on the scope

1

Step 1

Pick the pulse source.

2

Step 2

Slow the timebase until 2 to 4 beats show.

3

Step 3

Count the boxes from one beat to the next. Multiply by ms per box.

4

Step 4

Beats per minute = 60 ÷ seconds per beat.

Short answer 1 · Seconds from one beat to the next

Record the numbers

Short answer 2 · Beats per minute

Record the numberbpm

Sketch · Draw two beats.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · At 60 beats a minute, how many seconds pass between beats?

Reflection

This is a school signal, not a medical one. What would a real heart monitor need that this does not have?

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The Oscilloscope · Lesson 13 of 17

Noise and averaging

Real signals are fuzzy. Averaging cleans them up.

Name and date

Key words

noiseaveragingsweep

Main idea

Noise is random fuzz. Averaging many sweeps lets the fuzz cancel out.

In my own words

Try it · on the scope

1

Step 1

Turn noise on. Look at the fuzz.

2

Step 2

Set averaging to 4.

3

Step 3

Set averaging to 16.

4

Step 4

Compare the fuzz at 1, 4 and 16.

Short answer 1 · At which averaging setting was the line cleanest?

Record the numbersweeps

Short answer 2 · Roughly how many boxes of fuzz at averaging 1?

Record the numberboxes

Sketch · Draw the noisy trace, then the averaged one.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · What could add noise to a real measurement?

Reflection

Why does averaging many sweeps make noise smaller?

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The Oscilloscope · Lesson 14 of 17

AC and DC coupling

An offset lifts the whole wave. AC coupling drops the lift.

Name and date

Key words

couplingACDCoffset

Main idea

DC coupling shows everything. AC coupling drops the steady offset.

In my own words

Try it · on the scope

1

Step 1

Add an offset of 2 V.

2

Step 2

With DC coupling, watch the wave ride up.

3

Step 3

Switch to AC coupling. It comes back to the middle.

4

Step 4

Switch back and forth twice.

Short answer 1 · With DC coupling, how many boxes above the middle is the wave's centre?

Record the numberboxes

Short answer 2 · With AC coupling, how many boxes?

Record the numberboxes

Sketch · Draw the wave with DC coupling and the offset on.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · Name a signal that has both a steady part and a wiggling part.

Reflection

When would you want to hide an offset? When would you want to see it?

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The Oscilloscope · Lesson 15 of 17

The 10× probe

A 10× probe shrinks the signal ten times. Tell the scope, or the numbers lie.

Name and date

Key words

probe10×attenuation

Main idea

A 10× probe divides the signal by ten. The scope must be told, or its numbers are wrong.

In my own words

Try it · on the scope

1

Step 1

Plug in the 10× probe. The wave gets small.

2

Step 2

Read the height off the screen. Write it down.

3

Step 3

Set the scope's probe setting to 10×.

4

Step 4

Read the true height now.

Short answer 1 · Height read before telling the scope

Record the numberV

Short answer 2 · True height after the 10× setting

Record the numberV

Sketch · Draw the small wave and the corrected reading.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · If the scope shows 0.3 V with a 10× probe set to 1×, what is the true height?

Reflection

Why do people use a 10× probe at all?

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The Oscilloscope · Lesson 16 of 17

Design a measurement

A mystery signal. Find its frequency and its height on your own.

Name and date

Key words

measurementperiodpeak to peak

Main idea

A good measurement is planned: fit the signal, read the boxes, multiply, check.

In my own words

Try it · on the scope

1

Step 1

Pick the mystery signal.

2

Step 2

Fit it: 1 to 4 cycles, 3 to 7 boxes tall.

3

Step 3

Read the period. Compute the frequency.

4

Step 4

Read the height: boxes × volts per box.

5

Step 5

Type both numbers into the lesson.

Short answer 1 · Frequency you found

Record the numberHz

Short answer 2 · Height you found

Record the numberV

Sketch · Draw the mystery signal as you fitted it.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · Which reading do you trust more, height or frequency? Why?

Reflection

Which settings did you change first, and why?

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The Oscilloscope · Lesson 17 of 17

Write it up and hand it in

Open the worksheet, write your claim, and turn it in.

Name and date

Key words

claimevidencereasoning

Main idea

A write-up says what you found, shows the numbers, and explains why they make sense.

In my own words

Try it · on the scope

1

Step 1

Write one sentence: what a scope measures.

2

Step 2

Write one sentence: how you read a height.

3

Step 3

Write one sentence: how you read a frequency.

4

Step 4

Add your name and tap FINISHED.

Short answer 1 · A scope measures … (one sentence)

Record the number

Short answer 2 · How many lessons did you finish?

Record the numberlessons

Sketch · Draw your favourite trace from the course.

Ten boxes across, eight boxes tall, like the screen. Draw with a finger, a mouse or a pen.

Short answer 3 · What is one thing you would measure next with a scope?

Reflection

What was the hardest lesson, and what helped?

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